Contractor route vs DIY route
If a single main contractor is engaged on a labour-and-materials basis, the contractor invoices at 0% under VAT Notice 708 chapter 3 and the homeowner pays no VAT in the first place[HMRC 708]. The DIY route is for self-managed projects where the homeowner buys materials directly and pays VAT at point-of-sale, then reclaims after completion via VAT431NB[VAT431NB].
The 6-month claim window
The claim must be submitted to HMRC within 6 months of the completion certificate date (typically issued by the building-control body on final sign-off). Late claims are refused. Set a calendar reminder at handover.
What qualifies
Building materials physically incorporated into the dwelling: bricks, blocks, insulation, plaster, timber, fixed kitchens, sanitaryware, boilers, integral white goods, fixed flooring, paint, fixed lighting. Solar panels and battery storage qualify when physically incorporated.
What does not qualify
Professional fees (architect, SE, surveyor); plant hire; freestanding white goods, fitted carpets in some cases, garden furniture, external soft landscaping. Note: this is the area most claims trip up. Read VAT Notice 708 chapter 11 (DIY claims) carefully.
Documentation HMRC requires
Completion certificate; planning permission; all original VAT invoices in date order with VAT numbers visible; signed VAT431NB form; bank details. Allow 6-12 weeks for HMRC to process and pay the reclaim.